Froth flotation of ores with aromatic alcohol



Patented Apr. 19, 1949 FROTH FLOTATION OF ORES WITH -AROMAT!C ALCOHOL William'T. Bishop, Eugene J. Lorand, and John E. Reese, Wilmington, Del., assignors to Hercules Powder 'Company, Wilmington, Del., 2.

\ corporation of Delaware No Drawing. Application July 17, 1945, Serial No. 605,630

This invention relates to an ore flotation process and, more particularly, to a process for efliciently concentrating minerals by froth flotation in the presence of a secondary or tertiary aromatic alcohol having between 9 and 12 carbon atoms.

It is well known that pine oil, cresylic acid, creosote, and amyl alcohol are effective flotation reagents. This invention involves the utilization 'of new flotation agents which have'been found to bring about a more efficient separation than the above-mentioned flotation agents, and, in most cases, less agent is required to bring about a good separation.

11 Claims. (01. 209-466) calcareous gangue and containing about 1.7 to about 1.8% lead, was prepared in a 2000-gram flotation machine. Then, 0.15 pound of sodium sulfide per ton of ore, 0.05 pound of isopropyl xanthate per ton of ore, and the frother, as listed in Table I, were added. Air was drawn through the pulp, and the concentrate was removed for a period of 10 minutes. The results are listed in the following table. A controlwas run, using amyl alcohol and 75% of hard wood creosote as the frothing agent, in which case almost twice as much frother was used as in Examples 1 and 2.

l The B-p-cyinenol was prepared by air-oxidation of p-cymenc and contained about 10-15% of p-methyl acetophenone.

In accordance with this invention, it has been discovered that ores may be concentrated by subjecting a pulp or slurry of a ground ore to froth flotation in the presence of a secondary or tertiary aromatic alcohol having between 9 and 12 carbon atoms per molecule as a flotation agent in a more facile, eflicient, and economical manner than heretofore possible.

The nature and purpose of the invention have been generally indicated, and the following examples illustrate preferred embodiments.

EXAMPLES 1-2 Lead" ore flotation pulp, containing about 2500 grams of ore, composed of galena in a siliceous,

Exlmrtes 3-5 A 1010-gram sample of lead ore (same as in Examples 1-2), which is retained byan 8-mesh screen, was ground in a ball mill for 10 minutes with 1000 cc. of water. The ground ore was screened through'a 48-mesh screen and then transferred to a IOOO-gram flotation machine. Water was added to dilute the pulp to about 20% solids. Then 0.10 pound potassium isopropyl xanthate and 0.15 pound sodium hydroxide were added, and the pulp was conditioned for 10 minutes. The frothers given in Table II were' added,-

and a concentrate was removed for 10 minutes.

The results are given in Table II.

Table II E v Pound Per Cent Per Cent Per Cent Frother Per Lead in Lead in Lead amp 9 Ton Tailing Concentrate Recovery 3. wp-dlmethyl-benzyl alcohol. 0.12 0. 63. 7 87 4 e-dimethyl-bcnzyl alcohol 0. l2 0. 64 65. 2 84 5 a,c,d',a'-wtmmethyl-a,a'-

p-xylenedlol 0. 12 0. 53 65.0 87

Exmnns 8-8 A 1010-gram sample of a copper ore was ground for 15 minutes in a ball mill with 1000 cc. of water. The copper ore contained about 0.9% copper, chiefly in the form of chalcopyrite and pyrite in a greater abundance than the copper mineral and gangue composed of siliceous minerals. Lime was added in the amount given in Table III. The ground ore was screened through a 48-mesh screen other suitable gas is passed through the pulp. The desired minerals collect in the froth that is produced on the surface of the pulp, and then the froth is removed.

The flotation agent may be either a secondary or tertiary aromatic alcohol having between 9 and 12 carbon atoms per molecule. Monohydrie tertiary aromatic alcohols having 9 or 10 carbon atoms and dihydric tertiary aromatic alcohols and vthen t n fer ed to a momgmm flotation 10 having 11 or 12 carbon atoms are preferable. The machine. pulp was diluted to about 20% alcohols should have a balance between the polar Solids with water; and then 0.04 pound potassium and nonpolar part of the molecule so that good cyanide per ton of ore was added and the pulp frothing is obtained. Suitable compounds inconditioned for 10 minutes. Then 0.04 pound of ll m ,p-dirnethylbenzyl alcohol, sodium dithiophosphate was added as the collecl a,c-dimethylbenzyl lc hol, t y1-m hy tor and the various frothers as given in Table III. be yl a c o be yl a coho B The concentrate was removed for minutes. methylcuminyl alcohol, a-isobutylbenzyl alcohol,

Table III Pound Lime 00 per Example mother g ,g g, t, Giant. Riser, arrest 1 Per Cent Per Cent Per Cent Per Cent S-p-cymenol 0.18 3. 0.11 28.2 81 21.8 73- S-p-cymenoL 27- amyl aleohoL. 0.18 3 0.17 29.4 81 20.7 8-p-cymenol (pure) 0.24 2.5 0.17 31.8 82 17.0

I The S-p-cymenol was prepared by air-oxidation of p-eymene and contained about 10-16- of p-methyl acetophenone.

EXAMPLE 9 One thousand twenty grams of zinc ore, which was retained by an 8-mesh screen, was ground in a ball mill for 7 minutes with 1000 cc. of water. The zinc ore contained about 12% zinc as the sulflde, sphalerite. Pyrite and siliceous gangue were also present. The ground ore was screened through a 35-mesh screen and then transferred to a 1000-gram flotation machine. The pulp was dfluted with water to about solids and conditioned for 10 minutes with-.55 pounds of lime and 1.4-pounds of copper sulfate per ton of ore.

Then 0.16 pound of ethyl xanthate per ton of ore and the frother shown in Table II were added. Air was drawn through the pulp, and a concentrate removed for 10 minutes. The following results, using 8-p-cymenol and using pine oil, clearly show the advantages obtained using the frother of this invention.

In carrying out the froth flotation process, the ore or mineral to be concentrated is first finely ground in the presence of water to the desired size, depending upon the mineral to be treated, to insure that all of the gangue and the metalliferous components are liberated from each other. The ground mineral is then screened to remove the oversized materials. The resulting slurry or pulp is transferred to a flotation machine where it is mechanically agitated. The flotation reagents are added to the pulp either in the mill or in the flotation machine, depending on the ore that is treated. Water is added to adjust the pulp to the desired solids content. After the agents have been dissolved or dispersed, air or ,a,c:',a' tetramethyl a e p xylenediol, and

pure form or it may be mixed with other oilyproducts obtained from the air-oxidation of the corresponding hydrocarbon. For example, the products used in accordance with this invention may be the oily products obtained by oxidizing p-cymene or a mixture of p-cymene and pmethane in the liquid phase, an aqueous medium, or an alkaline medium with oxygen or air. The acids and unreaeted p-cymene are separated from the oily oxidation product. This oily product contains B-p-cymenol and p-methyl acetophenone. The p-methyl acetophonene also acts as a frothing agent. It is preferable to use an agent which contains at least 75% of the aromatic alcohol.

The flotation agent should be added in amounts from about 0.005 to about 5 pounds per ton of ore but, preferably, in amounts of 0.01 to 0.5 pound per ton of ore. The frothing agents are operable over a wide pH range.

In most cases, in order to get the most efllcient separation of the minerals from the ore, other flotation agents are used along with the frother. These may be (1) collectors, such as xanthates, mercaptans, organic sulfides, dithiophosphates, .thiocarbonates, thioureas, thiocarbonilide, azo and diazo compounds, etc.; (2) activating and conditioning agents, such as copper sulfate and other salts of copper, lead, zinc, etc.; alkali metal sulfide, lime, sodium hydroxide, sodium carbonate, cyanides, alkali metal silicates, etc.; (8) inhibitors, such as glue, starch, gelatin, etc.

The flotation agents disclosed in accordance with this invention may be used generally for the dressing of ores, including sulfide ores, oxides, and nonmetallic ores. The invention is especially applicable, however, to metallic ores, particularly ores containing sulfide minerals of zinc, lead, copper, iron, silver, etc., which may be simple or complex combinations.

Although the applicability of the flotation agent is generalfor conditioning ores or treating minerals, the conditions affecting the frothing operation are dependent, in addition to the froth flotation agent, on the size of the ore being treated, the temperature at which the treatment is being carried out, and the per cent solids in I the pulp. In each case, the particular conditions may be adjusted so as to permit the flotation agent to perform in a most economical and emcient manner.

The physical characteristics of the froth produced by an aromatic alcohol having between 9 and 12 carbon atoms are excellent. The froth is made up of fine bubbles which have sufficient strength to support the weight of the mineral coating. The froths are clear in respect to fine, slimy gangue present. When using lead and zinc ores; about one-half as much of the alcohol is required to produce the same froth and metallurgical results as is needed when pine oil or a mixture of amyl alcohol and a hard wood creosote is used.

What we claim and desire to protect by Letters Patent is:

1. In the method of concentrating ores, the step which comprises subjecting to froth flotation an aqueous pulp of the ore in the presence of a collector and an aromatic alcohol selected from ,the group consisting of secondary and tertiary alcohols having between '9 and 12 carbon atoms per molecule.

2. In the method of concentrating ores, the steps which comprise adding a collector and an aromatic alcohol selected from the group consisting of secondary and tertiary alcohols having between 9 and 12 carbon atoms per molecule to an aqueous pulp of the ore, agitating and aerating said pulp to form a froth containing the desired mineral values of said ore, and separating said froth.

3. In the method of concentrating ores, the steps which comprise adding a collector and 8-pcymenol to an aqueous pulp of the ore, agitating and aerating said pulp to form a froth containing the desired mineral values of said ore, and separating said froth.

4. In the method of concentrating ores, the steps which comprise adding a collectorand between about 0.005 pound and about 5 pounds of 8-p-cymeno1 per ton of ore to an aqueous pulp of the ore, agitating and aerating said pulp to form a froth containing the desired mineral values of said ore, and separating said froth.

5. In the method of concentrating ores, the steps which comprise adding a collector and 4!,- dimethylbenzyl alcohol to an aqueous pulp of the ore, agitating and aerating said pulp to form a froth containing the desired mineral values oi. said ore, and separating said froth.

froth.

7. In the method of concentrating ores, the steps which comprise adding a collector and ,,a',a' tetramethyl up p xylenediol to an aqueous pulp of the ore, agitating and aerating said pulp to form a froth containing the desired mineral values of said ore, and separating said froth.

8. In the method of concentrating ores, the steps which comprise adding a collector and between about 0.005 pound and about 5 pounds of ,e'-tetramethyl-a,a'-p-xylenediol per ton of ore to an aqueous pulp of the ore, agitating and aerating said pulp to form a froth containing the desired mineral values of said ore, and separating said froth.

9. In the method of concentrating metallic sulfide ore, the steps which comprise adding a collector and 8-p-cymenol to an aqueous pulp of said ore, agitating and aerating said pulp to form a froth containing the desired mineral values of said ore, and separating said froth.

10. In the method of concentrating metallic sulfide ore; the steps which comprise adding a collector and a,a-dimethylbenzyl alcohol to an aqueous pulp of said ore, agitating and aerating said pulp to form a froth containing the desired mineral values of said ore, and separating said froth.

11. In the method of concentrating metallic sulfide ore, the steps which comprise adding a collector and a,a,',a-tetramethyl-a,a'-p-xylenedial to an aqueous pulp of said ore, agitating and aerating said pulp to form a froth containing the desired mineral values of said ore, and separating said froth.

WILLIAM T. BISHOP. EUGENE J. LORAND. JOHN E. REESE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,302,466 Palmer Nov. 17, 1942 2,302,467 Palmer Nov. 17, 1942 Richards and Locke, Textbook of Ore Dressing, 1940, page 249,

Certificate of Correction Patent No. 2,467,369. April 19, 1949.

WILLIAM T. BISHOP ET AL. It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows:

Columns 3 and 4, Table 111, second column thereof, for 73- 8-p-eymenol, 27- amyl alcohol, read 78% 8-p-cymenol, 27% amyl alcohol; same table, footnote 1, for 10l5- read 10-15%; column 6, line 59, list of references cited, for the numeral 62 read 63; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Oflice.

Signed and sealed this 18th day of October, A. D. 1949.

THOMAS F. MURPHY,

Assistant Oommissz'oner of Patents. 

